Orthodontic brackets represent a principal component of all corrective orthodontic treatments devoted to improving a patient's occlusion. In conventional orthodontic treatments, an orthodontist or an assistant affixes brackets to the patient's teeth and engages an archwire into a slot of each bracket. The archwire applies corrective forces that coerce the teeth to move into correct positions. Traditional ligatures, such as small elastomeric O-rings or fine metal wires, are employed to retain the archwire within each bracket slot. Due to difficulties encountered in applying an individual ligature to each bracket, self-ligating orthodontic brackets have been developed that eliminate the need for ligatures by relying on a movable portion or member, such as a latch or slide, for retaining the archwire within the bracket slot.
There are generally two types of ligation of the archwire to the orthodontic bracket: passive ligation and active ligation. In passive ligation, a closure member bounds the archwire slot such that the archwire slot has a fixed width dimension (e.g., labially-lingually). Additionally, the archwire located in the archwire slot typically has a width dimension that is smaller than the width dimension such that there is a space or gap between the archwire and the archwire slot.
In contrast, in active ligation, an aspect of the bracket actively imposes a force onto the archwire to seat the archwire within the archwire slot such that there are generally no spaces or gaps and a snug fit is attained therebetween. The biasing of the archwire into the archwire slot may be achieved, for example, through the use of a resilient member on the bracket that acts on the archwire to push the archwire towards the base of the archwire slot.
During the early stages of orthodontic treatment, significant movement of the teeth is generally desired. This typically requires there to be significant movement of the archwire relative to the brackets on the teeth. Accordingly, during these early stages of treatment, passive ligation of the archwire may be desired to facilitate the relative movement between archwire and the brackets during these relatively large movements of the teeth. To achieve passive ligation, relatively small or thin archwires are often used to ensure sufficient space in the archwire slot.
During the finishing stages of orthodontic treatment, however, fine and precise movements of the teeth may be desired. These movements typically require excellent control of the archwire within the archwire slot. Thus, during these final stages of treatment, active ligation of the archwire may be desired to facilitate, for example, excellent torque and rotational control of the teeth. To achieve active ligation, generally large or thick archwires are often used to ensure a snug fit in the archwire slot.
While orthodontic treatment often proceeds according to the above treatment plan, i.e., passive ligation during early stages and active ligation during final stages, it may be desirable in some cases to deviate from that treatment plan. By way of example, when using a certain size archwire (e.g., a threshold size of archwire), it may be desirable to give the orthodontist or the clinician the option of selecting the type of ligation he or she desires for securing the archwire to the bracket. This may allow for greater variability in the treatment plan to meet the specific needs of any particular patient. Current orthodontic brackets, however, and especially self-ligating orthodontic brackets, typically do not provide the ability for the orthodontist to select between active and passive ligation of the archwire in an efficient and straight forward manner.
Thus, while self-ligating brackets have been generally successful, manufacturers of such brackets continually strive to improve their use and functionality. In this regard, there remains a need for self-ligating orthodontic brackets that allow an orthodontist or clinician to select between active and passive ligation of the archwire in an improved manner. In this way, orthodontists may develop treatment plans that more adequately meet the needs of patients.